Gas detecting apparatus



Dec. 14, 1937.

R. A. GANDY GAS DETECTING APPARATUS Filed Jah.

2 Sheets-Sheet l Ticrl.

Z N R Wm II! /A, Z

Dec. 14, 1937. R. A. GANDY I GAS DETECTING APPARATUS Filed Jan. 15, 1935 2 Sheets-Sheet 2 iiiiii IKWFFP INVENTOR 1 L a H N m a Z 5% Patented Dec. 14, 1937 UNITED STATES PATENT OFFICE 8 Claims.

Thisinvention relates to a gas detecting apparatus' or the like.

One of the objects of this invention is to provide a simple, inexpensive and practical gas detector that will be well adapted to meet the varying conditions of practical use. Another object is to provide a practical gas detecting apparatus of the above character which will be eflicient in action. Another object is to provide a durable gas detecting apparatus of the above character which will be reliable in operation. Another object is to provide a gas detecting apparatus of the above character whose use will be simple and which may be operated by unskilled users. Another object is to provide a gas detecting apparatus of the above character which will be easy to install. Another object is to provide a gas detecting apparatus of the above character which will give an instantaneous warning of the presence of an explosive mixture of gas vapor and will be entirely safe in operation. Other objects will be in part obvious and in part pointed out hereinafter.

This invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of the various possible embodiments of my invention,

Figure 1 is a diagrammatic representation of a cross section of a boat having my apparatus installed therein;

Figure 2 is a. vertical sectional view of a portion of my apparatus;

Figure 3 is a horizontal sectional view of my apparatus taken along the line 3-3 of Figure 2;

Figure 4 is a perspective view of a portion of my apparatus;

Figure 5 is a horizontal sectional view of my apparatus taken along line 5-5 of Figure 2;

Figure 6 is a plan view of the control mechanism of my apparatus; and

Figure 7 is a diagrammatical view of the electrical circuit of my apparatus.

Similar reference characters refer to similar parts throughout the several views of the. drawmes.

Referring now to the drawings in detail, a cross section of a boat (generally indicated at !U in Figure l) is taken through that portion of the hull in which the engine II is located and 4 my apparatus is shown as it would be preferably installed therein. Engine ll rests on supports Ila and llb and adjacent thereto and preferably positioned low in the hold of the boat is a container I5 which acts as an explosion chamber for my device. It is preferably removably secured to the boat by some means such as by bracket PM and positioned just above the maximum level of the bilge water.

Control panel I3 is preferably installed above deck l4 and preferably on the instrument panel of the boat which is usually situated adjacent steering wheel I2. Control panel I3 and explosion chamber 15 may be connected into the high tension circuit of the internal combustion engine H or may have a separate circuit, or both, all of which will be more fully described hereinafter. Thus the explosion chamber when in use on a boat will be situated where the richest gas vapor tends to collect and the control panel on which the warning of the presence of gas is given is located where it will be immediately noticed. It should be understood, however, that the use of my apparatus for detecting gas vapor in the holds of boats is only one of the many varied uses to which my apparatus is adapted.

The explosion chamber generally indicated at l5 in Figure 2 preferably consists of cylindrical casing 16 having removable cover plates I! and '18 at its opposite ends, all of which are constructed of metal and the construction of which is suiiiciently strong to withstand an explosion of gas vapor therein. Cover plate [8 has a vent i9 and cover plate I? has vents 20 and 2|, which vents are of such construction that no part of the explosive flame can reach externally of the explosion chamber 15. As these vents are preferably of identical construction, one only will be described.

Disposed within cover plate l8 (Figure 2) and generally indicated at 22 is a recess preferably threaded and circular in shape. Within this recess 22 I preferably screw a threaded hollow cap 222) which protrudes within the explosion chamber. Within the top of cap 22b I preferably provide a vent 23 which leads from the inside of Within this recess to the convex strip 25 and the outer edges of the convex strip 25 rest upon the cap 22b. (Figure 5.) A disc 26 is mounted within the recess 22 and rests upon the outer edges of the concave strip 24 and has a vent 21 in its center prefably the same size as vents 23 and 23a. This construction is repeated several times until a flame trap of ample strength and suificient interference has been placed between the explosion on the inside of the explosion chamber and the atmosphere outside of the explosion chamber to prevent any explosive. flame from reaching externally of the explosion chamber l5.

The members of this device collectively force any flame or hot gases which cay tend to pass to the outer air through a circuitous passage, and as these members are of high heat conducting power, they quickly cool these gases to a point far below ignition temperature.

Above vents I3 and 20 I have provided spring valves 2 and 6 which act as added precautions against an explosive flame reaching externally of explosion chamber l5. As they are of identical construction, I will therefore limit my description to one of these valves. Valve 2 (Figures 2 and 3) is a thin sheet of resilient metal connected to'cover plate 18 by means of screw 3. This spring valve 2 preferably has a cap 5 (Fig ure 3) to cover the vent 20 and a resilient arm 5 normally holdingcap 4 above this vent. When an explosion occurs, the force of the explosion forces cap 4 over the vent and prevents the explosive flame from reaching externally of the explosion chamber.

These devices also act to a certain degree to prevent the force of the explosion from immediately escaping the interior of the explosion chamber thereby to build up the internal pressure. Thus, I have provided an explosion chamber l5 having vents i9, 20, and 2| and valves 2 and 6 therein so constructed that the atmosphere surrounding the explosion chamber may have free access to the interior of the explosion chamber, and have eliminated the danger of an explosive flame reaching the atmosphere surrounding the explosion chamber, the vents and valves also serving as baffle plates to retain the force of the explosion.

Referring now to Figure 2, cover plate IT has a threaded recess therein which forms the walls of vent 20. Within this vent is screwed a threaded cap 28 of preferably the same construction as cap 22b except that the portion of the cap protruding within the explosion chamber I5 is threaded. A threaded metal sleeve 36 having cut-out portions 3| therein is screwed over the protruding portion of cap 28. At its opposite end sleeve 30 has a thread cut therein on its inner surface and an ignition device 33 having a sparking gap 32 mounted therein. This ignition device 33 is preferably in the form of an ordinary spark plug and therefore the thread in the sleeve 30 is preferably cut the same as that on an ordinary spark plug so that ignition device 33 may easily be changed whenever it is necessary.

Also passing through and extending inwardly from cover plate I! is a casing 48 preferably constructed of some insulating material such as fibre. Casing 48 extends externally of explosion chamber I5 suiiiciently to prevent a' fully insu- .lated high tension circuit wire 49, tightly fitted therein, from coming in contact with the explosion chamber l5 and acts as an insulator for the high tension circuit wire 49 up to the point where'the wire 49 is connected to a terminal 5 A conductor a is attached to the terminal at the top of spark plug 33 and extends from that point to the terminal 5!] thus forming a source of high tension current for the spark plug 33.

Below vent 2| a threaded cap 34 is screwed into cover plate I! leaving a portion thereof protruding below the surface of the cover plate I! and a threaded coupling 34a is screwed over this protruding portion. A metal sleeve 35 threaded at one end is screwed into coupling 34a. A second sleeve 36 preferably constructed from some insulating material fits within sleeve 35 and extends part way up into sleeve 35 from its innermost end. Slidably mounted in the opposite end of sleeve 35 isa piston 31 of greater diameter than the inner diameter of sleeve 36. A series of teeth 31a, 37b, 370 (Figure 4) cut into piston 31 surround its lower peripheral edge so that when piston 31 rests upon the upper edge of sleeve 36, if moisture leaks in through vent 2|, it will be able to pass between the piston 3'! and the sleeve 36' at this point. Preferably through the center of piston 3'! a threaded bolt (Figures 2 and 4) 38 extends downwardly so that, when teeth 37a, 31b, and 310 rest on the upper edges of sleeve 36, screw 38 will lie well within sleeve 36. 7

Within sleeve 36 and extending upwardly from its outer end toward the vent 2! are two contact arms 39 and 4-5 preferably constructed of some resilient metal. At theends of contact arms 39 and 56 are contact points 35 and 46 which are constantly being forced toward each other by the resilient forces in the contact arms. Each contact arm is secured to sleeve 35 by means of bolts 3! and 42 respectively and contact arm 39 is grounded to sleeve 35 and thus to the casing of the explosion chamber. Contact arm 66 is insulated from sleeve 35 by insulator 43 and is connected to terminal 44 which in turn is connected to terminal 52 by metal conductor l1. Between the contact points 45 and 45 of these arms screw 38 passes through a casing 41 constructed of insulating material and through two metal sleeves l8 and i9 which are threaded upon screw 38. Sleeve 16 preferably extends downwardly to the end of screw 38 and is of the same diameter as casing 41.

Screw 33 extends through casing 41, sleeves l8 and I3, and terminates below contact points 45 and 46 so that, when piston 31 rests against sleeve 36, casing 41 will rest between contact points 35 and 46. Screw 38 and sleeves l8 and 19 extend downwardly below casing 41 so that,

when piston 31 has been moved upwardly by a force such as an explosion and contact points 45 and have been permitted to meet, if piston 3'! rebounds from the end of the sleeve 35, sleeves l8 and 19 will be first driven between the contact points and the friction between the sleeves and the contact points 45 and 56 will prevent the casing 41 again being driven between the contact points. When sleeve 18 or 19 is between contact points 35 and 46, the circuit between terminal 44 and grounded bolt ll will still be complete as sleeves l8 and 19 are constructed of metal. Within the piston 31 I have provided a weight 310. which gives the piston sufiicient weight so that by shaking the explosion chamber l5, or striking it downwardly against a solid object, casing 41 may again be driven between the contact points 55 and 66 and the circuit will again be broken and the device restored to condition for use. Above vents 26 and 2| I have provided two curved tubes 83 and 8| which are preferably threaded Although they permit free acplosion chamber 5, they impede the entrance of dirt or other foreign matter into the explosion chamber. Thus, I have provided an eflicient switch in which a piston 31 is slidably mounted within a sleeve and has atmospheric pressure on one side so that the force of the explosion within .the explosion chamber will result in unequal pres- 1 sure on the opposite surfaces of piston 31 and the piston 31 will be driven upwardly causing a circuit to be grounded to the explosion chamber casing through'the meeting of contact points and 46, all as will be more fully described hereinafter.

Referring now to Figure '7, in which is shown a type of circuit that may be used in connection with explosion chamber |5, a source of voltage current, preferably a battery, is indicated at 54. One terminal of battery 54 is connected by conductor 56 to a breaker point 51 which in turn contacts one terminalof the primary coil 58 of an ordinary induction coil 59. The opposite terminal of primary coil 58 is connected through conductor 66 and spring switch 66 to the other terminal of battery 54 through conductor 55, which may be considered as a ground. Bridging switch 60 is a circuit 6| having therein a plug switch consisting of spring contacts 45 and 46 having the insulating spacer 41 between them. Circuit 64 of the secondary coil 63 of the induction coil 59 has a spark plug 33 and a neon tube 65 connected in series therein.

In operation, spring switch 60 is closed permitting a current to flow through conductors and 66 through the primary coil 58 and then back to the opposite terminal of battery 54 through breaker point 51 and conduit 56. This will vibrate the member 51 in the usual manner and induce a high voltage current in the secondary coil 63 which will flow through conduit 64 and thus through neon tube 65 and spark plug 33 causing a spark to occur between points 32 of the plug. As this spark plug 33 is situated within the explosion chamber I5, if an explosive mixture of gas vapor is present, the spacer 41 will be moved by the force of the explosion from between contacts 45 and 46, as has been described hereinabove, and permit circuit 6| to be completed. When switch 66 (Figures 1 and 7) is released it springs upwardly breaking its contact with conductor 55. However, if an explosion has occurred during the period when switch 68 was closed, the metal portion 13, 19 (Figure 2) of the plug switch 41 lies between contacts 45 and 46 (Figure 7) completing circuit 6| which bridges switch 66 and connects conductor 55 to conductor 66. Current thus continues to flow to the primary coil 58 through this circuit inducing a current in the high tension circuit 64 by way of secondary 63, which causes neon tube 65 to glow. To summarize, the user first presses down spring switch 66 which causes both spark plug 33 and neon tube 65 to operate. Then, when switch is opened,

*, if an explosion has occurred, switch 60 is bridged by circuit 6|, as pointed out above, causing the neon tube to continue to operate, warning the user that an explosion has occurred. If an explosion does not occur, neon tube stops glowing as soon as switch 66 is opened because circuit 6| has not been made; Thus the user may test for the presence of an explosive mixture at any desirable time, and the glowing of tube 65, when the switch is closed, shows that the mechanism is operating. If the tube continues to glow when the switchis open, it shows that an explosion has occurred.

Within circuit 6|, I have provided a switch 62 which normally is in a closed position but which may be opened to break the circuit. By this switch it is possible to break the flow of current to the primary coil 58 after an explosion has occurred, and thus make it possible for the user to break the source of current through the neon tube 65 after the warning has been observed.

Referring now to Figure 1, the explosion chamber I5 is shown mounted in the hold of a boat, electrically connected to the control panel l3 and to the ignition system of engine so that it may be operated either from the battery 54 through the control panel or by the ignition system of the engine. To operate the explosion chamber from the control panel l3, spring switch 60 is closed completing a circuit through conductor 55, battery 54, conductor 56, interrupter 51, primary coil 58, and conductor 66. This induces a high tension current in secondary coil 63, which flows to the spark plug in the explosion chamber through conductor 64, thence through the ground in the explosion chamber, through conductor 55, neon tube 65, and conductor 64 to the opposite side of the secondary coil. Thus the closing of spring switch 68 causes a sparking within the explosion chamber and also causes neon tube 65 to glow.

If an explosion occurs within the explosion chamber, conductor 6| will be grounded to conductor 55 through the plug switch 41 (Figures 2 and 7). Thus, when spring switch 60 is open the circuit to the primary coil 58 through conductor 66, switch 62, conductor 6|, conductor 55, battery 54 and conductor 56. This circuit is substantially similar to the circuit diagrammatically shown in Figure '7, which may be referred to for further details.

The ignition system of engine comprises battery 54, inductor 12, distributor 96 and a generator 93 operated in conventional manner by the motor. One terminal of battery 54 is grounded as at 82. The opposite terminal of the battery is connected to the primary coil 92 of inductor 12 by conductor 95. The opposite side of the primary coil is grounded as at 86, completing the circuit therethrough. The secondary coil 9| of the induction coil 12 has one terminal coni.

nected to the distributor and the other grounded as at 86. The distributor 98 is shown as having four contact points 98a, 93b, 98c, and 96d. This distributor would necessarily be used for a four cylinder engine. and the number of plugs it uses does not afiect the operation of my device. By way of illustration, one plug 1| of the engine is shown connected to contact point 980 of the distributor by conductor 98. Thus the circuit to this plug is completed through conductor 98, plug 1|, conductor 86, secondary coil 9| and conductor 96. A second conductor 81 is connected to contact point 96c and. leads to conductor 64, which is connected to the spark plug in the explosion chamber. The explosion chamber is grounded by ground 83. Thus every time a spark occurs at plug 1 a current will flow through conductor 91 to cause a spark in the gas detector as pointed out hereinbelow.

Generator 93 is connected to the two terminals of the battery 54 by conductors 84 and 81, conductor 81 preferably having a cutout switch 94 inserted therein to avoid overcharging the battery, and also a conventional interruptor 99. In

is completed 1 However, the size of the engine 'operatlomwhen switch 60 is open and engine II is operating, intermittent, sparks will occur within the explosion chamber. The current inducing the high tension current in the high tension circuit will be drawn either from the generator 93 or from battery 54, depending upon Whether the engine is operating or not. When the motor is operatingelectric'impulses fiow through conductor 91 intermittently and accordingly the neon 65 flashes intermittently. If an explosion occurs at any time the circuit to the primary coil 58 will be completed through the plug switch. This will cause high tension current to be induced in the secondary coil which in turn causes neon tube 65 to glow steadily. Thus the user'is immediately warned at any time an explosion occurs within the explosion chamber when the engine is in operation.

It may accordingly be seen that it is possible to determine at any time Whether or not the spark plug in the detector is operating, regardless of whether the motor is running or not. That is, current generated during the operation of the motor and current supplied by the battery are alternative sources, either of which is efiective to operate the gas detector.

From the generator 93 a connection 84 leads tothe ground wire 82, and another conductor 95 leads by way of cutout 94, inductor 'lZ, distributor 90 and conductor 9'! to the conductor 64 which, as hereinbefore set forth, leads in turn to the ignition device within the explosion chamber. The high tension current in conductor 91 is caused to flow intermittently and automatically by any desired means while the engine is running in such manner as not to interfere with the ignition system of the engine and yet to give at frequent intervals a spark discharge between the terminals of the spark plug 33 in the explosion chamber. In this manner so long as the engine is running, there is automatically provided means whereby the character of the contents of the explosion chamber will be intermittently tested at suitably frequent intervals. If at any time an explosion occurs due to current passing through the conductor 9?, the results hereinbefore described will follow and the contact members and 46 coming together will cause the illumination of the tubethus giving warning of the presence of gas in the hold of the vessel.

As shown in Figure 1, the warningtube 65 as well as the push button switch 60 are so connected as to be motmted upon a panel in some conveniently accessible portion of the boat such as a bulkhead at the forward end of the cockpit of an ordinary cruiser.

The details of the control panel l3 are better shown in Figure 6 of the drawings, and the arrangement of the parts will, it is believed, be readily understood. The switch member 62 by which the low tension circuit is interrupted is preferably of the swinging type, whereas the switch it is of the push button type, being operated by an insulating button indicated in dotted lines at it and extending forwardly through the cover plate of the panel. In like manner, this cover plate will. conceal all of the parts except the neon tube which is visible through an opening in.

the cover plate indicated by the dotted line 14. Also th upwardly turned insulating handle 15 of the switch 52 extends through an arcuate slot in the cover plate indicated by the dotted line 16.

safe in operation having all points of the high tension circuit well insulated with no metal parts of that circuit exposed adjacent the explosion chamber l5. It will thus be seen that there has been provided by this invention an apparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a gas detecting apparatus, in combination, an explosion chamber, a circuit including a source of current, an indicator connected to the circuit, igniting means positioned within the explosion chamber and connected to the circuit, switch means for closing the circuit to supply current to said igniting means and said indicator, and a second switch means connected in parallel with said first switch responsive to the occurrence of an explosion within the explosion chamber whereby the circuit will remain closed after the opening of said first named switch if an explosion has occurred. 2. Inc. gas detecting apparatus, in combination, an -explosion chamber, a circuit including a source of current, an indicator connecter-to the circuit, igniting means positioned within the explosion chamber and connected to the circuit, switch means for closing the circuit to supply current to said igniting means and said indicator, a second switch responsive to the occurrence of an explosion within the explosion chamber, and means for connecting said second switch to the circuit whereby the circuit will remain closed after the opening of said first named switch if an explosion has occurred.

3. In a gas detecting apparatus, in combination, an explosion chamber, a circuit including a source of current, an indicator connected to the circuit, igniting means positioned within the explosion chamber and connected to the circuit, an'

induction coil including an interrupter connected to said circuit, the primary of said coil being connected to said source of current and the secondary of said coil being connected to said indicator and said igniting means, a switch for closing" the circuit to' supply current to said primary whereby said secondary is energized to actuate said indicator and said igniting means, a second switch responsive to the occurrence of an explosion within the explosion chamber, and means for connecting said second switch to the circuit whereby the circuit will remain closed after the opening of said first switch if an explosion has occurred.

4. In a gas detecting apparatus, in combination, an explosion chamber, a circuit including a source of current, an indicator connected to the circuit, igniting means positioned within the exoccurrence of an explosion within the explosion chamber, "and means for connecting said second switch to the circuit whereby the circuit will remain closed after the opening of said first named switch if an explosion has occurred.

5. In a gas detecting apparatus, in combination, an explosion chamber, a circuit including a source of current, an indicator connected to the circuit, igniting means positioned within the explosion chamber and connected to the circuit, said indicator and said igniting means being connected in series, switch means for closing the circuit to supply current to said igniting means and said indicator, a second switch responsive to the occurrence of an explosion within the explosion chamber, and means for connecting said second switch to the circuit whereby the circuit will remain closed after the opening of said first named switch if an explosion has occurred.

6. In a gas detecting apparatus, in combination, an explosion chamber, a circuit including a source of current, an indicator connected to the circuit, igniting means positioned within the explosion chamber, an internal combustion motor having an ignition system including a distributor, one contact of which isconnected to said circuit, said indicator and said igniting means being energized from said distributor contact during the operation of the motor, said indicator being actuated steadily when energized by said source of current but actuated intermittently when energized from said distributor contact, switch means responsive to the occurrence of an explosion within the explosion chamber, and means for connecting said switch means to the circuit when an explosion occurs.

'7. In a gas detecting apparatus, in combination, an explosion chamber, a vent formed in said explosion chamber, means forming a flame trap in said vent whereby the surrounding atmosphere may circulate through the explosion chamber and the flame of an explosion within the explosion chamber is completely confined therewithin, ignition means within said chamber, a movable switch positioned within said chamber and movable to complete a circuit when an explosion occurs within the explosion chamber, means for maintaining said switch in its circuit closing position, and means associated with said switch and responsive to manipulation of the chamber to reset the switch after an explosion has occurred.

8. In a device of the nature described, in combination, means forming an explosion chamber to be positioned within the hold of a boat or the like to receive therewithin any explosive mixture of gases collecting in said hold, means for igniting an explosive mixture within said chamber, a circuit including a source of current positioned externally of said explosion chamber and having a switch for controlling said igniting means, an engine positioned within the hold of said boat, and means connecting said igniting means to the high tension circuit of said engine also whereby the user may test for the presence of gas in the hold of a boat by closing the switch before starting the engine and also obtain a continuous testing for the presence of gas when the engine is running.

RAYMOND ALFRED GANDY. 

